Power semiconductor modules are used in high power applications to switch high voltages and currents, and include multiple power semiconductors. Since each single semiconductor has a maximum voltage and current, the semiconductors have to be combined in parallel and/or in series within the power semiconductor module to enable their use in high power applications. To facilitate the manufacturing of such modules, they may include multiple substrates on which the power semiconductors are mounted. The substrates are provided with common contacts for emitter, collector and base contacts, so that the substrates can easily be connected in the power semiconductor modules. The substrates are mounted on a common base plate, which can be part of a housing of the power semiconductor module or which can be held within a housing of the power semiconductor module.
In known power semiconductor modules, four or six substrates may be combined, each provided with six power semiconductors including insulated gate bipolar transistors (IGBT), power diodes, reverse conducting insulated gate bipolar transistors (RC-IGBT), or other power semiconductors suitable for high power applications. The power semiconductors may be arranged in two rows on each substrate. For example, a substrate can include four IGBTs and two power diodes.
Important characteristics of a power semiconductor module are its size, heat generation, cooling and maximum power. To facilitate the use of power semiconductor modules, it is desired to provide modules with a compact size, which require little space for mounting, and which are capable of use with high currents. Due to the applied high power, power semiconductors generate an amount of heat which can damage the individual semiconductors or the entire power semiconductor module. It is also desired to achieve a good relation between maximum current and heat generation, so that the power semiconductor modules as a whole and all individual power semiconductors are not damaged during use. Therefore, it is also important to dissipate the heat generated in the power semiconductors within the module and away from the module.